Neurogenic bowel (NB) is the impairment of the gastrointestinal and anorectal function from a lesion in the nervous system, resulting in failure to evacuate the bowel (fecal constipation, fecal impaction) or failure to contain stool (fecal incontinence).
NB can be seen in multiple conditions, including spinal cord injury (SCI), brain injury, stroke, spina bifida, Parkinson’s disease (PD), amyotrophic lateral sclerosis, multiple sclerosis (MS), peripheral nerve injuries and diabetes mellitus, among others. Much of the literature on NB is in the SCI population.
Epidemiology including risk factors and primary prevention
Prevalence of NB depends on the diagnosis. Over 80% of SCI patients have some degree of bowel dysfunction, with moderate to severe symptoms reported by 39-50%.11 It has been reported that 95% of patients with SCI required at least one therapeutic procedure to initiate defecation.1 Fecal incontinence has been reported in up to 70% of patients with MS, 56% of patients with cerebral palsy, 68% of patients with spina bifida, 23% of patients with stroke, and 24% of patients with Parkinson’s disease. Constipation has been reported in up to 70% of MS patients, 25% of stroke patients, and 20-81% of people with Parkinson’s disease.3,12
The gastrointestinal system is controlled by the autonomic nervous system, including the enteric, parasympathetic, and sympathetic nervous systems. The enteric nervous system is located within the gut itself and controls peristalsis and secretion. Parasympathetic innervation includes the vagus nerve (upper GI tract to the splenic flexure of the colon) and sacral nerves 2-4 (to distal colon and rectum). Sympathetic innervation originates from T9-L2 (to colon and rectum). Parasympathetic activity generally promotes peristalsis and defecation, while sympathetic activity slows peristalsis and promotes storage. The external anal sphincter has somatic innervation from the pudendal nerve (S2-4) and is under voluntary control.11
Normal reflexes include the defecation reflex (stretch of rectal wall stimulates rectal wall contraction), rectoanal inhibitory reflex (stretch of rectal wall relaxes internal anal sphincter), and the gastrocolic reflex (stomach stretch stimulates colonic motility).11
Neurogenic bowel dysfunction can result from multiple factors, including autonomic dysfunction, altered reflexes, altered sphincter tone, altered sensation and strength, and mobility or cognitive impairments. The type of dysfunction depends on the level and severity of the lesion and is commonly divided into reflexic or areflexic bowel (Table 1). Lesions at or proximal to the conus medullaris typically result in a reflexic bowel, whereas lesions distal to the conus typically result in an areflexic bowel. In a reflexic bowel, there is increased colonic wall and anal sphincter tone. Stool propulsion still occurs due to intact reflexes but may be less efficient and shows prolonged colonic transit time. Due to increased sphincter tone and possible dyssynergia, reflexic bowel is less prone to incontinence, but may promote retention and constipation. With an areflexic bowel, there is decreased spinal cord mediated peristalsis, and colonic and sphincter tone is reduced. This results in very prolonged colonic transit times, constipation, and tendency for incontinence. Rectosigmoid emptying is reduced in both, but reflexic bowel can take advantage of reflex defecation.11
The dysfunction in PD is distinct and incompletely understood. GI dysfunction is thought to be one of the earliest and most common nonmotor symptoms in PD, related to lesions in the enteric nervous system and pelvic floor dystonia. Upper GI symptoms are also more prevalent compared to SCI.13,14
Table 1 – Features of Reflexic versus Areflexic Bowel Dysfunction
|Reflexic Bowel||Areflexic Bowel|
|Constipation and fecal retention||Constipation and incontinence|
|Delayed colonic transit, less delay in rectum||Very delayed colonic transit throughout|
|Anal area appears normal||Flattened scalloped appearance of anal area|
|Normal or increased anal sphincter tone||Reduced anal sphincter tone|
|Reflex defecation is present.||Absent reflex defecation|
|Anocutaneous and bulbocavernosus reflexes are present or increased||Anocutaneous and bulbocavernosus reflexes are absent or decreased|
|Target stool consistency is soft formed||Target stool consistency is firm but not hard|
|Prone to rectal prolapse|
|Bowel care every 1-3 days is recommended||Daily bowel care is recommended to avoid fecal incontinence|
|Use rectal suppositories to promote peristalsis and evacuation||Rectal suppositories are not usually effective|
|Digital stimulation can be used to assist in evacuation||Digital stimulation is not effective; manual evacuation may be necessary|
Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)
New onset/acute: After SCI, there is temporary loss or depression of all or most reflex activity below the level of the lesion, which may last hours to weeks (spinal shock). During this time period, there is less reflex-mediated defecation.4 Studies on the natural history of NB in other populations are lacking.
Subacute: In SCI, once spinal shock has resolved, a bowel program can be initiated. The underlying pathophysiology (reflexic vs areflexic) will guide the interventions to be used (Table 1).
Chronic/stable: During this time period, treatment continues using an appropriate bowel program. Hemorrhoids can develop if high pressures are present due to hard stool passage. In areflexic bowel, chronic passage of large hard stools can result in rectal prolapse with an overstretched, non-competent sphincter.2 There is some evidence that symptoms may become more severe with time since SCI.11
Specific secondary or associated conditions and complications
Complications due to neurogenic bowel include, but are not limited to, ileus, gastroesophageal reflux disease (GERD), autonomic dysreflexia (AD), pain, distention, nausea, anorexia, impaction, constipation, diarrhea, delayed evacuation, and unplanned evacuation. Severe complications may include fecal impaction, bowel obstruction, and megacolon. An appropriate bowel program should minimize or eliminate complications.4 Bowel dysfunction also correlates with depression and quality of life.11
Essentials of Assessment
This should include pre-injury gastrointestinal function and medical conditions, current bowel program, current symptoms including abdominal distention, respiratory compromise, early satiety, nausea, evacuation difficulty, unplanned evacuations, rectal bleeding, diarrhea, constipation and pain. History should also include defecation or bowel care frequency and medication use. Daily fluid intake, diet (amount of fiber intake and calorie frequency), activity level, components of bowel care, time for bowel program, and characteristics (amount, consistency, presence of blood) of the stool should also be explored.4 Standardized assessment forms exist, such as the International SCI Bowel Function Basic Data Set, SCI-QOL, and NBD score.11
The patient physical examination should be performed at onset and annually thereafter in stable situations. The examination should include a complete abdominal assessment, rectal examination, assessment of anal sphincter tone, anal sensation and voluntary contraction, and elicitation of anocutaneous and bulbocavernosus reflexes to determine if the patient has reflexic or areflexic bowel.4,6,7
Assessment should include patient’s ability to learn and/or to direct others with a bowel program, sitting tolerance, sitting balance, upper limb strength and proprioception, upper limb function, spasticity, transfer skills, actual and potential risks to skin, home accessibility, and equipment needs. This assessment should occur for both the patient and caregiver.2
Annual stool testing for occult blood should occur for patients over the age of 50. For patients experiencing diarrhea of unknown etiology, stool examination for fecal leukocytes, clostridium difficile toxin, and ova and parasites may be helpful in searching for a diagnosis.4,6,7
Fecal retention and megacolon are common diagnoses in patients with neurogenic bowel, thus flat plate x-ray of the abdomen may be warranted in patients with obstipation or constipation, and is useful to assess fecal load. Abdominal CT can be useful to further delineate emergent vs non-emergent GI issues including obstruction.11 After age 50, colonoscopies, sigmoidoscopies, double-contrast barium enemas or computerized tomographic (CT) colonography (virtual colonoscopy) should be performed every 5-10 years, as recommended by screening guidelines.4,6
Supplemental assessment tools
A dietary record and bowel care record can be useful to determine appropriate diet and bowel program changes. Bowel care record should include position, stimulation method, assistive techniques, time to results, and stool properties (amount, color, consistency).4 Colonic transit time testing with radiopaque markers, scintigraphy or a wireless motility capsule may be useful to confirm pathophysiology and assess response to treatment. Anorectal manometry (ARM) with/without pelvic EMG and pudendal nerve conduction studies may be useful to assess pelvic floor dysfunction and dyssynergia in motor incomplete injuries, and can help distinguish constipation from fecal incontinence. Defecography can be used when ARM is inconclusive.11
The home environment should be evaluated, and appropriate adaptive equipment for bowel care should be prescribed. Commonly, shower chairs with seats designed to allow access to the perineal area are necessary. Padded seats and tilt-in-space features can be beneficial. The equipment should be inspected and fit assessed to avoid pressure ulcers related to equipment.4,7,11
Social role and social support system
The patient’s and caregiver’s knowledge and performance of, and confidence in, the recommended bowel management program should be assessed at each follow-up appointment. Barriers to learning or implementing the bowel program should be assessed, including mental health, cognition, literacy, language, readiness, and cultural issues.11
Rehabilitation Management and Treatments
Available or current treatment guidelines
Clinical Practice guidelines from the Consortium of Spinal Cord Medicine were updated in 2020.11 The goals of an effective bowel program are to provide predictable and effective elimination within a reasonable amount of time, reduce unplanned evacuations, and reduce evacuation problems and gastrointestinal complaints. The design of a bowel program should take into account attendant care, personal goals, life schedules, role obligations of the individual, and self-rated quality of life. In order to prevent complications, a bowel program should be initiated early and should be scheduled at the same time of the day to establish a habit-forming response. Thirty minutes prior to bowel care, food or liquids may need to be ingested to stimulate the gastrocolic response. Bowel care should be scheduled on average every 1-2 days to prevent chronic colorectal overdistention. Frequency of bowel care will be dependent on amount and type of intake, activity, type of impairment, and pre-injury patterns of elimination.4-6 A summary of bowel care agents can be found elsewhere.8,11 There is conflicting evidence for abdominal massage, and Valsalva is not recommended. Fiber supplementation is not universally recommended, but may be beneficial to some.11,12,13
Components of a bowel management program include11:
- Diet and fluid management
- Physical activity
- Oral medications
- Rectal medications
- Scheduled bowel care
- Rectal evacuation methods
Overview of Basic Bowel Management According to Type of Bowel Dysfunction11
|Reflexic Bowel||Areflexic Bowel|
|Adequate fluid and fiber intake, exercise, and individual care plan||Adequate fluid and fiber intake, exercise, and individual care plan|
|Daily but minimum 3 times/week||One or more times per day|
|Goal Bristol stool scale 3-4||Goal Bristol stool scale 3-4 (towards 3)|
|Digital rectal stimulation and manual evacuation||Manual removal|
|Oral medications||Oral medications|
- Reflexic bowel: Initial bowel care may consist of a chemical stimulant onto the rectal mucosa. After waiting for the stimulant to activate, the patient is placed in an upright or side-lying position and digital stimulation is performed until evacuation occurs. The goal for stool consistency is soft formed, allowing easy evacuation with rectal stimulation.4, 7
- Areflexic bowel: Initial bowel care may consist of upright or side-lying position, performing gentle manual evacuation until the rectum is stool free. The goal for stool consistency is firm formed stool that can be retained between bowel care sessions and allow easy manual evacuation.4,7
Diet, fluids, activity, and oral medications help attain and maintain appropriate stool consistency. It is important to make changes to a bowel program systematically, changing one factor at a time (diet, fluids, activity, schedule, position, rectal stimulant medications, mechanical stimulation, assistive techniques, or oral medications). Adjustments to the bowel program are made based on the response to treatment, and should closely involve the patient and caregiver. There should be ongoing monitoring for GI or intra-abdominal complications. Aging can have an influence on bowel function as well, thus modifications may be necessary over time.4,6,11
Other rectal evacuation methods may be used if the above measures are inadequate. Enemas may be used intermittently to help with constipation. Transanal irrigation (TAI) can be used when basic bowel programs are ineffective. During TAI, fluid is pumped into the colon via a cone or catheter, generally while on a commode/toilet. Evidence supports the effectiveness of TAI in reducing constipation, incontinence, and defecation time.11,12 Pulsed irrigation can be used for impaction in a hospital/clinic setting.11
Surgical procedures: surgical interventions are reserved for severe bowel dysfunction when other treatments have failed, and after thorough education regarding risks, benefits, and complications. Colostomy is the most common surgical option, though there is no consensus on the optimal timing. The malone antegrade continence enema (MACE) involves the creation of a small stoma using the appendix, through which a catheter can be inserted to perform enema irrigation. These surgical interventions have been shown to improve quality of life.4,6,11
Patient & family education
This is essential. As described in previous sections, there should be understanding of the different types of neurogenic bowel and the bowel programs that are required to achieve proper care. Bowel care program training should be given to both the patient and caregivers, including education on potential complications. Social and emotional support should be available to help manage actual or potential disabilities associated with neurogenic bowel. The Consortium for Spinal Cord Medicine Consumer Guideline on Neurogenic Bowel is a great resource for patients and families (even when SCI is not the underlying etiology).9
Cutting Edge/ Emerging and Unique Concepts and Practice
Newer oral medications have been approved for chronic constipation or IBS-C, including chloride-channel activators (e.g. linaclotide, plecanatide, lubiprostone), serotonin4 agonists (e.g. prucalopride), and bile-acid analogs (e.g. chenodeoxycholic acid). Their efficacy in neurogenic bowel is unclear.11
Functional magnetic stimulation involves a magnetic field used to stimulate spinal nerves. Small observational studies show potential improvement in reducing colonic transit time. Level of evidence remains low. Various forms of functional electrical stimulation are being investigated, including sacral nerve stimulation, sacral anterior root stimulation, posterior tibial nerve stimulation, e-stim of abdominal muscles, perianal e-stim, and epidural e-stim. Overall quality of evidence remains low and higher quality studies are needed.10,11,13
Gaps in the Evidence- Based Knowledge
Additional research is needed to further understand the pathophysiology of neurogenic bowel dysfunction, including the role of the gut microbiome.
Higher quality studies are needed to understand the role of diet, supplements, fiber, and probiotics on neurogenic bowel management.
- Higgins PD, Johanson JF. Epidemiology of constipation in North America: A systematic review. American Journal of Gastroenterology. 2004;99:750-759.
- Steins SA, King JC. Neurogenic bowel: Dysfunction and rehabilitation. In: Braddom RL, ed, Physical Medicine and Rehabilitation. Vol 1. 3rd ed. Philadelphia, PA: Saunders; 2006:637-650.
- Preziosi G, Emmanuel A. Neurogenic bowel dysfunction: Pathophysiology, clinical manifestations and treatment. Expert review of gastroenterology & hepatology. 2009;3(4):417-423.
- Consortium for Spinal Cord Medicine. Clinical practice guidelines: neurogenic bowel management in adults with spinal cord injury. Journal of Spinal Cord Medicine. 1998;21:248-293.
- Spinal Cord Injury Centres of the United Kingdom and Ireland. Guidelines for management of neurogenic bowel dysfunction after spinal cord injury. http://www.rcn.org.uk/__data/assets/pdf_file/0019/253036/CV453N_full_doc.pdf. Accessed May 1, 2011.
- Linsenmeyer TA, Stone JM, Steins SA. Neurogenic Bowel. In: Delisa J. Physical Medicine and Rehabilitation: Principles and Practice, Volume 2, 4th edition, Philadelphia, PA: Lippincott Williams & Wilkins; 2005:1641.
- Stiens S, Goetz L, Strayer J. Neurogenic bowel dysfunction: Evaluation and adaptive management. In: O’Young B, Young M, Stiens S, eds. Physical Medicine and Rehabilitation Secrets. 4th ed. Philadelphia, PA: Mosby Elsevier; 2008:531-538.
- Appendix 4; Bowel Care Medications. In: Gonzalez-Fernandez M, Friedman JD, eds. Physical Medicine and Rehabilitation Pocket Companion. Vol 1. 1st ed. New York, NY: Demos; 2011:326-3279.
- Consortium for Spinal Cord Medicine. Neurogenic bowel: what you should know. http://www.scicpg.org/cpg_cons_pdf/BWLC.pdf. Accessed May 1, 2011.
- Mowatt, G., Glazener, C., Jarrett, M. Sacral nerve stimulation for faecal incontinence and constipation in adults. 2007. The Cochrane Library.
- Consortium for Spinal Cord Medicine Clinical practice guidelines: Management of Neurogenic Bowel Dysfunction in Adults after Spinal Cord Injury. 2020. https://pvacf.org/wp-content/uploads/2020/10/CPG_Neurogenic-Bowel-Recommendations.single-6.pdf. Accessed March 28, 2021.
- Coggrave M, Norton C, Cody JD. Management of faecal incontinence and constipation in adults with central neurological diseases. Cochrane Database of Systematic Reviews 2014, Issue 1. Art. No.: CD002115.
- Cotterill N, Madersbacher H, Wyndaele JJ, et al. Neurogenic bowel dysfunction: Clinical management recommendations of the Neurologic Incontinence Committee of the Fifth International Consultation on Incontinence 2013. Neurourology and Urodynamics. 2018;37:46-53.
- Awad RA. Neurogenic bowel dysfunction in patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease. World J Gastroenterol. 2011 December 14; 17(46):5035-5048.
Original Version of the Topic
Michelle Poliak, MD, Sara Liegel, MD. Neurogenic Bowel. 11/10/2011.
Previous Revision(s) of the Topic
Michelle Poliak, MD, Sara Liegel, MD. Neurogenic Bowel. 9/18/2015.
Philip Chen, MD
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